The guy is scamming you because Canon does not diagnose problems over the phone. It usually takes a couple of days after they receive the item to send you their diagnosis plus the cost of repairs if you choose to fix it. Don't respond to him (or to MDJak ) & stop worrying so much. The deal is closed.
Love the new avatar, Maureen. I think Skip needs to contribute a layout of you in G&N. I'm looking forward to it.
BTW, this thread has run its course. I've said all that needs to be said.
As to the comment above which invites the buyer to start litigation, first we're not talking about a 250,000 dollar home that fell down when the big bad wolf blew on it.
Second, let's just wildly imagine that he did start litigation. Imagine the time and potential money involved in defending one's self.
It's been said over and over. There is NO fault here by the seller. He has NO requirement to do anything.
But as others have said, individual professionalism, the ability to sleep comfortably at night, knowing that you replied to the individual in a nice way, asked for proof of Canon's supposed diagnosis, none of that means you're making yourself liable at all.
By the way, OP, Maureen really Luvs me, so you can respond. In fact, you may wind up with a title of world's greatest lens seller, or LensHopper, otay, Grasshopper?